SEVENTEENTH AND EIGHTEENTH CENTURIES 2.95 

 and medical subjects; but on closer inspection we find that it deals with a 

 number of problems that engaged the minds of the author's contemporaries, 

 although from a curious point of view. 



Erasmus Darwin's natural philosophy 

 The work begins with the assertion that spirit and matter are the foundations 

 of nature; then life is defined as being due to a special force, which, after 

 Haller, is called irritability and by aid of which all life-phenomena are ex- 

 plained in a somewhat peculiar manner. All manifestations of life, both phys- 

 ical and psychical, are due to the contraction of fibres, which is induced by 

 irritation; by "idea" the author understands a contraction of the fibres that 

 form the direct sensory organs. La Mettrie himself could hardly have ex- 

 pressed himself more materialistically, but Erasmus Darwin is by no means 

 a materialist as the term was understood by his own age; true, he refers to 

 the sceptic Hume's inquiries into cause and effect, but at the same time cer- 

 tifies his invincible faith in the Bible, quoting verses of the Psalms on the 

 wisdom of the Creator and citing the words of Moses in the Book of Genesis 

 touching the creation of Eve from Adam's rib as a proof of his own theory 

 of reproduction. This latter theory, more than anything else that Erasmus 

 Darwin wrote, attracted great attention, which indeed it undoubtedly de- 

 served. To a certain extent it is reminiscent of Caspar Friedrich Wolff's theory 

 of evolution — that is to say, in so far as it is markedly epigenetic. Whether 

 the author had recourse to Wolff is not clear from his work — possibly he 

 had on second-hand information. But, above all, his theory is pronouncedly 

 animalculistic; just as the whole basis of his theory of life rests on the as- 

 sumption of "irritable" fibres being the basic substance of all living things, 

 so the origin of the embryo is a " filament, ' ' which is derived from the father 

 and to which the mother only gives nourishment. As a result of this latter 

 the embryo grows, by no means, however, as a result of the development 

 of ready-formed rudiments, but through the addition of fresh matter. The 

 author seeks to disprove the preformation theory by arguments both serious 

 and facetious; Bonnet's incapsulation theory in particular seems to him ex- 

 ceedingly ludicrous; the dimensions of the infinite number of embryos con- 

 tained one inside the other remind him of how St. Anthony was tempted 

 by twenty thousand devils, all dancing on a pin-point. In further confirma- 

 tion of his epigenesis theory he declares that the male "filament" which 

 gives rise to the new individual is manifestly influenced by the nourishment 

 which the mother provides; any resemblance between mother and child is 

 due thereto, as is particularly shown in bastards. And still further: the con- 

 ditions under which the parents live clearly influence the character of their 

 offspring, as is proved by the new varieties obtained from domestic animals; 

 organs which the animals need are produced by irritation in the parts of the 

 body which form them, and they are afterwards inherited by their progeny. 



